[C language] data types and calculations

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The actual calculation of the data we contact is not only the integer type, then the C language program using only int will also bring some problems.

Start with an example:

#include <stdio.h>int  main () {    int  A;    printf (" Enter a number, get the result divided by 3:");    scanf ("%d", &a);    printf ("%d", A/3); // 3, the fractional part is automatically abandoned.    return 0 ;}

Workaround:

1. Use floating-point numbers for division operations (integers and floating-point numbers to do operations, C will convert integers to floating-point numbers, then floating-point arithmetic)

#include <stdio.h>intMain () {DoubleA; Doubleb; printf ("Please enter two numbers, such as 1 2, to calculate the result of dividing: \ n"); scanf ("%LF%LF", &a, &b); Input with%LF printf ("The result of the division is:%f \ n", A/b); %f for Outputreturn 0;}

2. Change the integer value directly to a floating-point value participation operation

#include <stdio.h>int  main () {        printf ("%f" ) 10.3/3);  // 3.333333    return 0 ;}

Data type:

Integer

Int

scanf ("%d");

printf ("%d", 5);

Floating point number

Double

scanf ("%lf", &a);

printf ("%f", 10.0);

Calculation:

#include <stdio.h>intMain () {//calculates the time difference between 1 hours and 30 minutes and 3 hours 20 minute    /*steps: 1. Use a variable to store the value 2. Set the conversion method (Formula): The hour takes the minute difference to divide by 60 to take the integer part, the minute is the minute difference divides 60 takes the remainder 3. Get Results*/        intHour1, minute1; intHour2, Minute2; scanf ("Please enter the hour and minute of time 1:%d%d", &hour1, &minute1);//read-In user input valuesscanf"Please enter the hour and minute of time 2:%d%d", &AMP;HOUR2, &minute2);
int T1 =HOUR1 * + minute1;
int t2 = HOUR2 * + minute2;
int t = T2-T1;

printf ("Time difference is%d hours%d minutes", T/60, t%60); More efficient than the following way

    /*
printf (" time difference is%d hours%d minutes ", (hour2*+minute2)-(hour1* +minute1) )/, ((hour2* +minute2)-(hour1* +minute1));
*/
       return 0 ;}

Averaging

#include <stdio.h>intMainintargcConst Char*argv[]) {    //averaging    intb; printf ("Please enter two number:"); scanf ("%d%d", &a, &b); printf ("average value is:%f", (A + B)/2.0);}

Operator Precedence: + (positive),-(negative), * (multiply),/(except),% (remainder), + (plus),-(minus), = (Assignment)

The value of the interchange variable:

Since the program is step-up, if you simply assign a value, and then only get two identical values, you need a third variable.

#include <stdio.h>int  main () {    int5;     int 8 ;     int C;         = A;     = B;     = C;        printf ("a=%d b=%d", A, b);}

@ Black eyed poet <www.chenwei.ws>

[C language] data types and calculations