\n

Calling functions in C++<\/p>\n

\/\/ function example<\/h1>\n

\n

#include<\/a> <iostream><\/dfn>\nusing<\/var> namespace<\/var> std;\n\nint<\/var> addition (int<\/var> a, int<\/var> b)\n{\n  int<\/var> r;\n  r=a+b;\n  return<\/var> r;\n}\n\nint<\/var> main ()\n{\n  int<\/var> z;\n  z = addition (5,3);\n  cout << \"The result is \"<\/kbd> << z;\n}

This program is divided in two functions: <\/span>addition<\/code> and <\/span>main<\/code>. Remember that no matter the order in which they are defined, a C++ program always starts by calling <\/span>main<\/code>. In fact, <\/span>main<\/code> is the only function called automatically, and the code in any other function is only executed if its function is called from <\/span>main<\/code> (directly or indirectly).<\/span>

In the example above, <\/span>main<\/code> begins by declaring the variable <\/span>z<\/code> of type <\/span>int<\/code>, and right after that, it performs the first function call: it calls <\/span>addition<\/code>. The call to a function follows a structure very similar to its declaration. In the example above, the call to <\/span>addition<\/code> can be compared to its definition just a few lines earlier:<\/span>

 
<\/span>The parameters in the function declaration have a clear correspondence to the arguments passed in the function call. The call passes two values, <\/span>5<\/code> and <\/span>3<\/code>, to the function; these correspond to the parameters <\/span>a<\/code> and <\/span>b<\/code>, declared for function<\/span>addition<\/code>.<\/span>

At the point at which the function is called from within main, the control is passed to function <\/span>addition<\/code>: here, execution of <\/span>main<\/code> is stopped, and will only resume once the <\/span>addition<\/code> function ends. At the moment of the function call, the value of both arguments (<\/span>5<\/code> and <\/span>3<\/code>) are copied to the local variables <\/span>int a<\/code> and <\/span>int b<\/code> within the function.<\/span>

Then, inside <\/span>addition<\/code>, another local variable is declared (<\/span>int r<\/code>), and by means of the expression <\/span>r=a+b<\/code>, the result of <\/span>a<\/code>plus <\/span>b<\/code> is assigned to <\/span>r<\/code>; which, for this case, where <\/span>a<\/code> is 5 and <\/span>b<\/code> is 3, means that 8 is assigned to <\/span>r<\/code>.<\/span>
<\/code><\/pre>\n<\/section>\n
#TC1017<\/a> #Mastery11<\/a><\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"
        Calling functions in C++\/\/ function example#include <iostream>
\nusing namespace std;<\/p>\n
int addition (int a, int b)
\n{
\n  int r;
\n  r=a+b;
\n  return r;
\n}<\/p>\n
int main ()
\n{
\n  int z;
\n  z = addition (5,3);
\n  cout << “The result is ” << z;… Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":115,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4,3,26],"tags":[330,324,398,328,95,128,40],"_links":{"self":[{"href":"https:\/\/kenscourses.com\/tc101winter2015\/wp-json\/wp\/v2\/posts\/9543"}],"collection":[{"href":"https:\/\/kenscourses.com\/tc101winter2015\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/kenscourses.com\/tc101winter2015\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/kenscourses.com\/tc101winter2015\/wp-json\/wp\/v2\/users\/115"}],"replies":[{"embeddable":true,"href":"https:\/\/kenscourses.com\/tc101winter2015\/wp-json\/wp\/v2\/comments?post=9543"}],"version-history":[{"count":1,"href":"https:\/\/kenscourses.com\/tc101winter2015\/wp-json\/wp\/v2\/posts\/9543\/revisions"}],"predecessor-version":[{"id":9544,"href":"https:\/\/kenscourses.com\/tc101winter2015\/wp-json\/wp\/v2\/posts\/9543\/revisions\/9544"}],"wp:attachment":[{"href":"https:\/\/kenscourses.com\/tc101winter2015\/wp-json\/wp\/v2\/media?parent=9543"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/kenscourses.com\/tc101winter2015\/wp-json\/wp\/v2\/categories?post=9543"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/kenscourses.com\/tc101winter2015\/wp-json\/wp\/v2\/tags?post=9543"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}