CODEWITHSUNDEEP
cfunction-pointers
Uchiha Lucky CS
Uchiha Lucky CS

Reputation: 46

c program compiles fine but closes unexpectly

#include<stdio.h>
#include<string.h>
#include<malloc.h>

char *sum(char nn1[],char nn2[]){
    int i,j,s,max=0,c=0,reslen=0;
    max=(strlen(nn2)>strlen(nn1))?strlen(nn2):strlen(nn1);
    char *str=(char*)malloc(max+1);
    char n1[max],n2[max];
    char st[max+1];

    for(i=0;i<max;i++){
        n1[i]='0';n2[i]='0';
    }

    for(i=max-strlen(nn1),j=0;j<strlen(nn1);j++){
        n1[i]=nn1[j];
        i++;
    }

    for(i=max-strlen(nn2),j=0;j<strlen(nn2);j++){
        n2[i]=nn2[j];
        i++;
    }


    for(i=max-1;i>=0;i--){
        s=(n1[i]-'0')+(n2[i]-'0')+c;
        st[i+1]=s%10+'0';
        c=s/10;
    }

    if(c){
        reslen=max+1;
        st[0]='1';
    }else{
        reslen=max;
        for(i=0;i<=max;i++)
            st[i]=st[i+1];
        st[i]='\0';
    }

    for(i=0;i<reslen;i++){
        str[i]=st[i];
    }

    if(strlen(str)!=reslen){
        str[reslen]='\0';
    }


    return str;

}

int main()
{
    unsigned int n,i;
    scanf("%d",&n);
    char *s0=sum("0","0");
    char *a[n];
    a[n]=malloc(10000);
    for(i=0;i<n;i++)
        scanf("%s",a[i]);

    for(i=0;i<n;i++)
        s0=sum(s0,a[i]);

    printf("%s",s0);

    return 0;
}

The above program closes unexpectly. I run this program in gcc, first scan no. of input and then scan numbers in string format and then perform sum function. Please fix error.

The sum function working fine without scanf() in main function, but it closes when using it with scanf().

Upvotes: 0

Views: 44

Answers (1)

Pras
Pras

Reputation: 4044

a is not allocated properly You should allocate it in the loop prior to taking input in it with scanf

a[n]=malloc(10000);// remove this statement, a[n] is out of bound too

for(i=0;i<n;i++)
{
    a[i] = malloc(10000); // allocate inside loop
    scanf("%s",a[i]);
}

Upvotes: 2

Related Questions