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Converting a float to a string function in c languange

Dear all,
I have a c program, and I am searching for a function like "itoa" to allow me add a float to a string.
Any idea on how can I achieve that?
1 Solution
Daniel Van Der WerkenIndependent ConsultantCommented:
Looks like there is no standard C library for this. You need to write it yourself. However, it's a fairly standard thing to want to do and there are many ways out there.
// Converts a floating point number to string.
void ftoa(float n, char *res, int afterpoint)
    // Extract integer part
    int ipart = (int)n;
    // Extract floating part
    float fpart = n - (float)ipart;
    // convert integer part to string
    int i = intToStr(ipart, res, 0);
    // check for display option after point
    if (afterpoint != 0)
        res[i] = '.';  // add dot
        // Get the value of fraction part upto given no.
        // of points after dot. The third parameter is needed
        // to handle cases like 233.007
        fpart = fpart * pow(10, afterpoint);
        intToStr((int)fpart, res + i + 1, afterpoint);

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Here is a link:
#include <stdio.h>
  char string[100];
  float f=1.0/3.0;
hassanayoub85Author Commented:
Where is the intToStr function?
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hassanayoub85Author Commented:
I dont want to use sprintf
Daniel Van Der WerkenIndependent ConsultantCommented:
It's in the article:
 // Converts a given integer x to string str[].  d is the number
 // of digits required in output. If d is more than the number
 // of digits in x, then 0s are added at the beginning.
int intToStr(int x, char str[], int d)
    int i = 0;
    while (x)
        str[i++] = (x%10) + '0';
        x = x/10;
    // If number of digits required is more, then
    // add 0s at the beginning
    while (i < d)
        str[i++] = '0';
    reverse(str, i);
    str[i] = '\0';
    return i;

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// C program for implementation of ftoa()
// reverses a string 'str' of length 'len'
void reverse(char *str, int len)
    int i=0, j=len-1, temp;
    while (i<j)
        temp = str[i];
        str[i] = str[j];
        str[j] = temp;
        i++; j--;

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hassanayoub85Author Commented:
I tried it but it didnt worked!
Hugh McCurdyCommented:
Can you be more specific about what you want?

Are you concerned with buffer overflow?
Karrtik IyerSoftware ArchitectCommented:
What are your concerns with sprintf, why you do not want to use it? Can you please specify your exact requirement?

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