Programs that had been made up to now were programs of all one-way traffic.
In a word, execute the sentence in the writing order from start to finish.
It was the simplest mechanism saying coming to ending if the sentence was lost.

If it is a really simple program, even this : though it manages to become.
It comes to a standstill at once when complex even a little processing is done.

Change the content of processing according to the condition to solve this problem.
There is money-> roast meat table d'hote and had - > bamboo basket Sova
The judgment on [noyouna] , condition is needed without fail.

In the world of computer, it is not ..the value of the numerical value.. ..another.. if it is said the condition.
In addition, only the comparison of two numerical values becomes a condition to put it concretely and it gets it.

If ([ifu]) sentence is prepared in C language as a sentence judged according to the condition.
The if sentence compares the values of two numerical values, and does the processing division based on the result.
The usage of the if sentence becomes as follows.

 
If (conditional expression) Sentence;

[ The   truth   ]
It means numerical values (Even the negative value :) other than 0 by how to call the conditional judgment.

[   Imitation   ]
It means 0 by how to call the conditional judgment.

 
#include <stdio.h> 

int main(void)  
{
	int suuti = 10;  
	if (suuti) printf("%d\n",suuti);  
	return 0;
}

10

[   Initialization   ]
Substitute the numerical value at the same time as declaring the variable.

The if sentence might be seen the sentence without the usage considerably only by reading the foregoing paragraph.
Anyway, only because whether 0 or not so can be judged.

However, if a usual calculation is combined with the if sentence, a more advanced comparison is possible.
For instance, when the number as which the value is the same is subtracted mutually, the answer : naturally It becomes 0.
If this character is used, the judgment of the value becomes possible by the subtraction.
Judge The following program uses the character, and the input number : 10.

 
#include <stdio.h> 

int main(void)  
{
	int suuti;  
	scanf("%d",&suuti);  
	If (suuti - 10) Printf ("The input value :  10 \n");  
	return 0;
}

10   Input data

135   Input data
The input value 10. Then, it is not.

Then, the operator only for the comparison is prepared in C language.
Use the == operator when you examine whether two numerical values are equal.
This operator calculates, that the result truly becomes it when two values are equal.

[   = and ==   ]
Even the professional has what makes a mistake in = and == carelessly well.
= A right, left numerical value is a comparison equal. the substitution of ..peel.. [hidari] for the variable and ==
First of all, doubt here when it doesn't move as thought.

 
#include <stdio.h> 

int main(void)  
{
	int suuti;  
	scanf("%d",&suuti);  
	If (suuti == 10) Printf ("The input value :  10 \
	n");  return 0;
}

10   Input data
The input value,

135   Input data