why input isn't being taken as i wanted?

-1

In this program i want to get a input where will be a string with some int.if no values were not given then, the program will just show the total amount.

But here, in the 1st case if i use a string with number,then there is 2 output.

Example input:

4

donate 100

report

donate 500

Example output:

0

100

100

0

But notice here i got chance of 3 times to input string,but output is 4 time.
So, can anyone tell me why this program acting weird?

#include<stdio.h>

#include<stdlib.h>

int main()

{

    int T, total=0, val=0;

    char  input1[20];



    scanf("%d",&T);



    while(T--)

    {

        scanf(" %s",input1);

        val=-1;



        val=atoi(input1);

        total+=val;



        printf("nInput="%s" val="%d"n", input1, val);



        if(val != -1)

            printf("%dn",total);



    }

}

edited Dec 5 '18 at 14:21

gsamaras

51.9k24107191

asked Nov 21 '18 at 16:12

mahin hossen

958

2

scanf(" %s", input1); reads till the next whitespace. first scanf will read donate and the second 100.

– Osiris
Nov 21 '18 at 16:16

Why not just add a line of code to log what's in input1 and what's in val right before the if and figure it out yourself?

– David Schwartz
Nov 21 '18 at 16:19

1

@mahinhossen If you want to read a string until new line you should use scanf(" %[^n]s",input1);

– Osiris
Nov 21 '18 at 16:30

1

@mahinhossen Right, so you do want them separate. You want to be able to ignore the "donate" and process the "100". That's most easily done if they're separate. If they're together, you'd just have to separate them because you want to handle the two things differently.

– David Schwartz
Nov 21 '18 at 16:40

1

@mahinhossen Your scanf is fine. You just need to add code to ignore the input if it's not a number. Your choice of atoi was not a good one, since it has no error detection.

– David Schwartz
Nov 21 '18 at 17:22

|
show 7 more comments

-1

In this program i want to get a input where will be a string with some int.if no values were not given then, the program will just show the total amount.

But here, in the 1st case if i use a string with number,then there is 2 output.

Example input:

4

donate 100

report

donate 500

Example output:

0

100

100

0

But notice here i got chance of 3 times to input string,but output is 4 time.
So, can anyone tell me why this program acting weird?

#include<stdio.h>

#include<stdlib.h>

int main()

{

    int T, total=0, val=0;

    char  input1[20];



    scanf("%d",&T);



    while(T--)

    {

        scanf(" %s",input1);

        val=-1;



        val=atoi(input1);

        total+=val;



        printf("nInput="%s" val="%d"n", input1, val);



        if(val != -1)

            printf("%dn",total);



    }

}

edited Dec 5 '18 at 14:21

gsamaras

51.9k24107191

asked Nov 21 '18 at 16:12

mahin hossen

958

2

scanf(" %s", input1); reads till the next whitespace. first scanf will read donate and the second 100.

– Osiris
Nov 21 '18 at 16:16

Why not just add a line of code to log what's in input1 and what's in val right before the if and figure it out yourself?

– David Schwartz
Nov 21 '18 at 16:19

1

@mahinhossen If you want to read a string until new line you should use scanf(" %[^n]s",input1);

– Osiris
Nov 21 '18 at 16:30

1

@mahinhossen Right, so you do want them separate. You want to be able to ignore the "donate" and process the "100". That's most easily done if they're separate. If they're together, you'd just have to separate them because you want to handle the two things differently.

– David Schwartz
Nov 21 '18 at 16:40

1

@mahinhossen Your scanf is fine. You just need to add code to ignore the input if it's not a number. Your choice of atoi was not a good one, since it has no error detection.

– David Schwartz
Nov 21 '18 at 17:22

|
show 7 more comments

-1

In this program i want to get a input where will be a string with some int.if no values were not given then, the program will just show the total amount.

But here, in the 1st case if i use a string with number,then there is 2 output.

Example input:

4

donate 100

report

donate 500

Example output:

0

100

100

0

But notice here i got chance of 3 times to input string,but output is 4 time.
So, can anyone tell me why this program acting weird?

#include<stdio.h>

#include<stdlib.h>

int main()

{

    int T, total=0, val=0;

    char  input1[20];



    scanf("%d",&T);



    while(T--)

    {

        scanf(" %s",input1);

        val=-1;



        val=atoi(input1);

        total+=val;



        printf("nInput="%s" val="%d"n", input1, val);



        if(val != -1)

            printf("%dn",total);



    }

}

edited Dec 5 '18 at 14:21

gsamaras

51.9k24107191

asked Nov 21 '18 at 16:12

mahin hossen

958

In this program i want to get a input where will be a string with some int.if no values were not given then, the program will just show the total amount.

But here, in the 1st case if i use a string with number,then there is 2 output.

Example input:

4

donate 100

report

donate 500

Example output:

0

100

100

0

But notice here i got chance of 3 times to input string,but output is 4 time.
So, can anyone tell me why this program acting weird?

#include<stdio.h>

#include<stdlib.h>

int main()

{

    int T, total=0, val=0;

    char  input1[20];



    scanf("%d",&T);



    while(T--)

    {

        scanf(" %s",input1);

        val=-1;



        val=atoi(input1);

        total+=val;



        printf("nInput="%s" val="%d"n", input1, val);



        if(val != -1)

            printf("%dn",total);



    }

}

c string input

edited Dec 5 '18 at 14:21

gsamaras

51.9k24107191

asked Nov 21 '18 at 16:12

mahin hossen

958

edited Dec 5 '18 at 14:21

gsamaras

51.9k24107191

asked Nov 21 '18 at 16:12

mahin hossen

958

edited Dec 5 '18 at 14:21

gsamaras

51.9k24107191

edited Dec 5 '18 at 14:21

gsamaras

51.9k24107191

edited Dec 5 '18 at 14:21

gsamaras

51.9k24107191

asked Nov 21 '18 at 16:12

mahin hossen

958

asked Nov 21 '18 at 16:12

mahin hossen

958

asked Nov 21 '18 at 16:12

mahin hossen

958

2

scanf(" %s", input1); reads till the next whitespace. first scanf will read donate and the second 100.

– Osiris
Nov 21 '18 at 16:16

Why not just add a line of code to log what's in input1 and what's in val right before the if and figure it out yourself?

– David Schwartz
Nov 21 '18 at 16:19

1

@mahinhossen If you want to read a string until new line you should use scanf(" %[^n]s",input1);

– Osiris
Nov 21 '18 at 16:30

1

@mahinhossen Right, so you do want them separate. You want to be able to ignore the "donate" and process the "100". That's most easily done if they're separate. If they're together, you'd just have to separate them because you want to handle the two things differently.

– David Schwartz
Nov 21 '18 at 16:40

1

@mahinhossen Your scanf is fine. You just need to add code to ignore the input if it's not a number. Your choice of atoi was not a good one, since it has no error detection.

– David Schwartz
Nov 21 '18 at 17:22

|
show 7 more comments

2

scanf(" %s", input1); reads till the next whitespace. first scanf will read donate and the second 100.

– Osiris
Nov 21 '18 at 16:16

Why not just add a line of code to log what's in input1 and what's in val right before the if and figure it out yourself?

– David Schwartz
Nov 21 '18 at 16:19

1

@mahinhossen If you want to read a string until new line you should use scanf(" %[^n]s",input1);

– Osiris
Nov 21 '18 at 16:30

1

@mahinhossen Right, so you do want them separate. You want to be able to ignore the "donate" and process the "100". That's most easily done if they're separate. If they're together, you'd just have to separate them because you want to handle the two things differently.

– David Schwartz
Nov 21 '18 at 16:40

1

@mahinhossen Your scanf is fine. You just need to add code to ignore the input if it's not a number. Your choice of atoi was not a good one, since it has no error detection.

– David Schwartz
Nov 21 '18 at 17:22

scanf(" %s", input1); reads till the next whitespace. first scanf will read donate and the second 100.

– Osiris
Nov 21 '18 at 16:16

Why not just add a line of code to log what's in input1 and what's in val right before the if and figure it out yourself?

– David Schwartz
Nov 21 '18 at 16:19

@mahinhossen If you want to read a string until new line you should use scanf(" %[^n]s",input1);

– Osiris
Nov 21 '18 at 16:30

@mahinhossen Right, so you do want them separate. You want to be able to ignore the "donate" and process the "100". That's most easily done if they're separate. If they're together, you'd just have to separate them because you want to handle the two things differently.

– David Schwartz
Nov 21 '18 at 16:40

@mahinhossen Your scanf is fine. You just need to add code to ignore the input if it's not a number. Your choice of atoi was not a good one, since it has no error detection.

– David Schwartz
Nov 21 '18 at 17:22

|
show 7 more comments

1 Answer
1

active

oldest

votes

Simply add logging and the answer will be obvious:

#include<stdio.h>

#include<stdlib.h>

int main()

{

    int T, total=0, val=-1;

    char  input1[20];



    scanf("%d",&T);



    while(T--)

    {

        scanf(" %s",input1);

        val=-1;



        val=atoi(input1);

        total+=val;



        printf("nInput='%s' val='%d'n", input1, val);



        if(val != -1)

            printf("%dn",total);



    }

}

Then run it and give it your input:

4

donate 100



Input='donate' val='0'

0



Input='100' val='100'

100

report



Input='report' val='0'

100

donate 500



Input='donate' val='0'

100

As you can see, your expectation that you'd somehow get a -1 value in val if atoi wasn't given a number is incorrect.

answered Nov 21 '18 at 16:22

David Schwartz

138k14145230

add a comment |

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1 Answer
1

active

oldest

votes

1 Answer
1

active

oldest

votes

Simply add logging and the answer will be obvious:

#include<stdio.h>

#include<stdlib.h>

int main()

{

    int T, total=0, val=-1;

    char  input1[20];



    scanf("%d",&T);



    while(T--)

    {

        scanf(" %s",input1);

        val=-1;



        val=atoi(input1);

        total+=val;



        printf("nInput='%s' val='%d'n", input1, val);



        if(val != -1)

            printf("%dn",total);



    }

}

Then run it and give it your input:

4

donate 100



Input='donate' val='0'

0



Input='100' val='100'

100

report



Input='report' val='0'

100

donate 500



Input='donate' val='0'

100

As you can see, your expectation that you'd somehow get a -1 value in val if atoi wasn't given a number is incorrect.

answered Nov 21 '18 at 16:22

David Schwartz

138k14145230

add a comment |

Simply add logging and the answer will be obvious:

#include<stdio.h>

#include<stdlib.h>

int main()

{

    int T, total=0, val=-1;

    char  input1[20];



    scanf("%d",&T);



    while(T--)

    {

        scanf(" %s",input1);

        val=-1;



        val=atoi(input1);

        total+=val;



        printf("nInput='%s' val='%d'n", input1, val);



        if(val != -1)

            printf("%dn",total);



    }

}

Then run it and give it your input:

4

donate 100



Input='donate' val='0'

0



Input='100' val='100'

100

report



Input='report' val='0'

100

donate 500



Input='donate' val='0'

100

As you can see, your expectation that you'd somehow get a -1 value in val if atoi wasn't given a number is incorrect.

answered Nov 21 '18 at 16:22

David Schwartz

138k14145230

add a comment |

Simply add logging and the answer will be obvious:

#include<stdio.h>

#include<stdlib.h>

int main()

{

    int T, total=0, val=-1;

    char  input1[20];



    scanf("%d",&T);



    while(T--)

    {

        scanf(" %s",input1);

        val=-1;



        val=atoi(input1);

        total+=val;



        printf("nInput='%s' val='%d'n", input1, val);



        if(val != -1)

            printf("%dn",total);



    }

}

Then run it and give it your input:

4

donate 100



Input='donate' val='0'

0



Input='100' val='100'

100

report



Input='report' val='0'

100

donate 500



Input='donate' val='0'

100

As you can see, your expectation that you'd somehow get a -1 value in val if atoi wasn't given a number is incorrect.

answered Nov 21 '18 at 16:22

David Schwartz

138k14145230

Simply add logging and the answer will be obvious:

#include<stdio.h>

#include<stdlib.h>

int main()

{

    int T, total=0, val=-1;

    char  input1[20];



    scanf("%d",&T);



    while(T--)

    {

        scanf(" %s",input1);

        val=-1;



        val=atoi(input1);

        total+=val;



        printf("nInput='%s' val='%d'n", input1, val);



        if(val != -1)

            printf("%dn",total);



    }

}

Then run it and give it your input:

4

donate 100



Input='donate' val='0'

0



Input='100' val='100'

100

report



Input='report' val='0'

100

donate 500



Input='donate' val='0'

100

As you can see, your expectation that you'd somehow get a -1 value in val if atoi wasn't given a number is incorrect.

answered Nov 21 '18 at 16:22

David Schwartz

138k14145230

answered Nov 21 '18 at 16:22

David Schwartz

138k14145230

answered Nov 21 '18 at 16:22

David Schwartz

138k14145230

answered Nov 21 '18 at 16:22

David Schwartz

138k14145230

add a comment |

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